and btw when saving to SD the CPU is at 15% maximum. On Wed, Jun 6, 2012 at 8:41 PM, Emmanuel Touzery <[email protected]> wrote:
> Hello, > > I have a Hauppage hvr-1900 that I use with an old PC, but that PC has the > usual downsides: it's big, loud and power-hungry. So I bought a raspberry > pi, hoping to use it to control the USB hauppage and use it for TV > recording. > > The driver works beautifully even though the pi is an ARMv6 device. All I > had to do was compile the kernel with the driver enabled and copy the > firmware and then it literally worked out of the box. > > But then of course there is a but ;-) > > It cuts when saving the video. There are drop-outs in the video. > > I googled the topic and found this: > http://comments.gmane.org/gmane.linux.drivers.pvrusb2/2006 > > And this helped. Well with chrt it freezes the pi after a while, but with > nice -20 I think it doesn't cut anymore for AV IN mpeg2 videos. I'm not > 100% sure but I watched 15 minutes of video and there was no cut. I'll need > more thorough testing to be 100% sure though. However for DVB-T recording > the cuts are still there, and I just can't manage to get rid of them. > Besides that flywheel app, and using a fifo, I've tried overclocking the > pi, building a non-preempt kernel (just in case), stopping as many daemons > as I could on the linux userspace, but nothing helps. I have measured the > SD card on which I write to write at 3Mb/s and more (up to 4). The mpeg2 > stream is ~1Mb/s. And in fact here we have SD h264 dvb-t so the stream that > gets written to the SD card has a much lower bitrate when recording dvb-t > (and that cuts) than from av-in (which let's say doesn't cut). So in theory > it's not the SD card writing speed which is the bottleneck. > > Of course it's possible that the AV in mpeg2 stream still gets cut but > that thanks to the error resilience in mpeg2 it's not that seen, while in > h264 at the cuts, the video gets corrupted for a short time and you can't > miss it. > > Anyway, I'm a bit of a loss on this one. Is the CPU or the I/O (from > hauppage or to SD) on the pi just too slow, or does anybody have an idea > how to make it work? Specifically for DVB-T, I was told that the kernel > does PID filtering in software. Maybe it slows things down, or is it that > fast that even on a lowly CPU like that pi's, it could for sure be done > realtime? I guess I can't turn it off and save the full unfiltered stream? > Though then my SD card bandwidth could start being a problem I guess. > > Anyway, any advice is welcome. I'm not giving up, but I'm definitely > running out of ideas... > > emmanuel > _______________________________________________ pvrusb2 mailing list [email protected] http://www.isely.net/cgi-bin/mailman/listinfo/pvrusb2
